Jolliffe, Clifford Mark (1999) The design of hybrid stepping motors aided by three dimensional finite element analysis. PhD thesis, University of Warwick.

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Abstract

Though the hybrid stepping motor has a long and proven history, in terms of toughness,
accuracy of position and the ability to operate in open loop, motor performance
improvements can still be made in terms of the physical structure of the motor's
components. It is impossible to build a complete solution of the hybrid stepping motor
using simple analytical functions or equivalent circuit representations. This is due to the
difficulties introduced by the motor's highly non-linear three dimensional magnetic
structure, of which the doubly salient tooth structure, axial magnet, and back iron all
complicate the situation. However, with the recent advances in three dimensional finite
element software a comprehensive study of the motor has been achieved in this thesis.
This has allowed improvements to simpler two dimensional based mathematical models,
which allow faster computation of the motor's electromagnetic performance. To aid
modelling, novel equations which accurately model today's high permeability steels have
been developed. These are shown to be more accurate than the established Jiles-Atherton
method. Inductance calculations of the steel's flux paths have been comprehensively
improved by the use of elliptical functions. The thesis concludes with the design of two
quite individual new machines. The first dramatically improves a motor's power output,
smoothness, noise levels, and resonance by modifying the tooth structure. The second uses
soft magnetic composite materials to provide an isotropic path for cross lamination flux
which flows in a stator's back iron. Both new designs are shown to offer a significant
improvements to the high speed torque capability of the hybrid stepping motor.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Stepping motors, Finite element method -- Computer programs, Inductance
Official Date:	January 1999
Dates:	Date Event January 1999 Submitted
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Pollock, Charles ; Michaelides, Alex
Sponsors:	Stebon Ltd. ; Great Britain. Dept. of Trade and Industry (DTI) ; Science and Engineering Research Council (Great Britain) (SERC) ; University of Warwick. Dept. of Engineering
Extent:	xv, 261, [70] p.
Language:	eng

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